So is mastery for Holy still a big deal?

So Im gleaning from the threads Haste is more the way to go for Holy at this point. Will mastery be as big a deal as it was before later on in tiers or have the changes for priests just made it not as crucial as Haste at this point?

I would say don't bother with the 5th tick of unglyphed Renew until iLVL 470+. I was running with iLVL 463 in 25man this week, 8.2k Spirit and I reforged all Haste/Crit to Mastery, I just didn't bother with the extra tick.

Renew did do a fair bit of my healing but I fail to see why I'd go for Haste to 12.51% > Mastery at this stage. The vast majority of my healing was done by instant cast direct healing spells as I (for the majority of the fight) used Inner Will to maximise HPM - at the end switching to Inner Fire for PoH spam. For this reason, getting that 5th tick and losing all the Mastery probably wouldn't do that much in terms of overall healing throughput, so until I hit 10k+ Spirit and gear to support the 5th tick, I'd advise Mastery > 12.51% Haste.

Now I've started on Heroics modes I can say Mastery is doing very nicely on 25 man. It would help if you clarified which raid size you were suggesting Haste over Mastery on - but at this stage of an expansion, given mana regen, I can't see why Haste is better beyond Mastery after the first tick anyway.

Raids:
Given how tight mana can be before you get into the five digit spirit range, I would actually also recommend going for mastery over haste. At least for now. Mastery allows you to spend less mana, and until you get to that point, every point of mana saved counts.

That said, haste really starts to shine when mana is less of a limiter. I really believe that haste is the best throughput stat for holy. While they are supposed to be mathematically equivalent, mastery very frequently just turns into overhealing, while haste offers you far more control over when to spend mana, and allows you to burn mana when it is needed - thus increasing your effective healing. I've been a haste stacker for many years due to this, and that sentiment hasn't really changed.

But I don't regret my decision to go for mastery in the gearup process. Where I in cata was always screaming for more mana, stacking mastery has allowed me to remain far more "cool headed" in that department. It's still tight. It's just not murdering me. That said - I still have problems getting mastery to heal for more than 8-9% of my total effective healing, so I'm not wholly sure if just stacking crit wouldn't have been just as fine.

Heroics:
Meh, stack what you can get your hands on. It doesn't really matter.

I'm enjoying nearly fully haste for the Lightwell/spring extra tick breakpoint - 4717 then going mastery. It works really well with PoH spam and EoL has only been about 10% of my healing since the PoH/PoM buff (and Cascade).